These phones have a big battery/charging problem. We have three
at or shop, charge them for fifteen hours, & run them till they run right
down, otherwise they won't last very long at all!! have a look here at
the reviews. You can "very carefully" put a load accross the battery
pack, to "run it down", then charge it for fifteen hours, but you must let
it run right down. Rono.

http://reviews.cnet.com/Panasonic_KX...-20604770.html